Ophiocordyceps sinensis (Berk.) Sung (synonym: Cordyceps sinensis (Berk.) Sacc.), classified under phylum Ascomycota, class Sordariomycetes, order Hypocreales, family Ophiocordycipitaceae and genus Ophiocordyceps, is a complex of a larva corpus and fungal stroma which originates from the larva of Hepialidae parasitized by Cordyceps spp. (Sung et al., 2007; Yue et al., 2013.). As a traditional Chinese medicine having pharmacological effects such as immunoregulation, anti-bacteria effect, antitumor effect, anti-aging effect, and reducing blood sugar and fat, it is recognized as “the three treasures of traditional Chinese medicine” together with ginseng and pilose antler.
Ophiocordyceps sinensis is a species endemic to the Qinghai-Tibet Plateau and merely found in four countries, China, Bhutan, India and Nepal. In China, it is usually found at an altitude of 3500 to 5000 meters, mainly in provinces such as Xizang, Sichuan, Qinghai, Yunnan, and Gansu (Yue et al., 2013). As the effects of Ophiocordyceps sinensis have been verified, it has gained worldwide tremendous attention (Buenz et al., 2005) resulting in an increase in global sales. Due to special habitat requirements, limited resources and high price, Ophiocordyceps sinensis resource has been overexploited such that the production in most areas has been decreased to below 10% of the production of 25 years ago (Yin et al., 2011), and thus, the increasing demand has outstripped the supply. Resource exhaustion, huge demand and government protection have caused a rapid rise of prize thereof. Moreover, wild Ophiocordyceps sinensis has been listed as a Class II protected species in China. In order to protect the ecosystems of the Qinghai-Tibet Plateau and the Ophiocordyceps sinensis resource and provide extensive use of Ophiocordyceps sinensis in human health, artificial cultivation is the only option.
Artificial rearing of ghost moth, which is a host insect of Cordyceps spp., is an important part of the artificial cultivation of Ophiocordyceps sinensis. The priority for artificial rearing of host insects is to provide diet for the insects. At present, natural feeds, mainly pieces of roots of Polygonaceae plants or carrots, are used in the rearing of ghost moths. However, natural feeds have problems such as huge limitation from the natural environment and seasonal supply shortage. Due to individual differences of the plants, it is difficult to achieve standardization. Moreover, since complete sterilization is unavailable, they are prone to pathogen contamination. Therefore, there is an urgent need to develop an artificial diet for ghost moths, which can avoid these problems and allow the ghost moths to grow regularly with consistent physiological features.